As digital technologies have developed, various types of electronic devices are widely utilized, such as a smart phone, a tablet Personal Computer (PC), a Personal Digital Assistant (PDA), an electronic organizer, a notebook, a wearable device, or the like. The electronic devices have reached the level of mobile convergence which includes the functions of other devices. For example, an electronic device can provide a call function such as a voice call and a video call, a message transmission/reception function such as a Short Message Service (SMS)/Multimedia Message Service (MMS) and an electronic mail (e-mail), an electronic organizer function, a photography function, a broadcast reproduction function, video playing function, music playing function, an Internet function, a messenger function, a game function, a Social Networking Service (SNS) function, and the like.
An electronic device having a photography function may have a camera supporting an auto focus (AF) function. When an AF is performed in the electronic device, the AF may configure a focus area for which the AF is performed in advance. For example, the focus area may be the central area of an LCD or view finder, a touched area, a face recognition area, or the like.
However, an AF processing method of a conventional electronic device uses a method which configures an AF area and focuses on a subject in the configured AF area.
An AF processing method of an electronic device can designate and deploy an AF area in a particular area of a screen (e.g., the center of a screen, a face recognition or a user selected location), and focus on subjects in the designated AF area. In this case, if a subject is not accurately located within the AF area and is biased or has a size narrower than the AF area, the electronic device cannot accurately perform an AF function due to by undesired image information in a configured AF area. In addition, in a case where a face recognition AF method is used, if an AF area which has been recognized as a face area cannot be accurately configured, the electronic device may cause an AF failure. Further, even in a case where a target subject is properly located in the configured AF area, an AF failure may occur. For example, when a configured AF area is slightly dark or is too bright, an electronic device cannot sufficiently acquire AF caldulation data and thus may cause an AF failure. Further, when a subject in a configured AF area moves, an electronic device cannot perform an AF for the moving subject.